The effect of habitual athletics training on muscle and tendon adaptation in young and older elite athletes.

INTRODUCTION Muscles and tendons adapt in response to mechanical loading (Arampatzis et al., 2007). However, different time courses of muscle and tendon adaptation in response to training (Mersmann et al., 2016) may cause discordance within the muscle-tendon unit (MTU), increasing injury risk. We analysed the triceps surae (TS) muscle strength and Achilles tendon (AT) stiffness in young adult elite athletes over one season, in order to detect potential training-induced discordance between muscle and tendon adaptation. Following this, we examined the effect of habitual athletics training on young and older athletes’ TS MTU mechanical properties, using a cross-sectional design.